Just for my curiosity, what are processes happening,when I press buy button in software center ? . I just noticed that it updates software cache when I pressed buy button. It means it adds a temporary repository for that app?

1 Answer
1

After clicking on the Buy button, Ubuntu Software Center will prompt
you to login or create an Ubuntu Single Sign On account.

Ubuntu Single Sign On (Ubuntu SSO) is a service provided by Canonical
Ltd that allows users to login to multiple websites and access
multiple services. Use your Ubuntu SSO to login to the following
Canonical websites:

Launchpad

Ubuntu One

Ubuntu Shop

PURCHASING SOFTWARE

If you already have an Ubuntu Single Sign On account, proceed with
your software purchase:

In the More Info screen, click on Buy

Login to your Ubuntu Single Sign On account

Review the Quantity, Description and Amount of your software
purchase

Enter your Billing address

Enter your Billing information

Click Review Payment to proceed (or cancel to stop)

Review your payment information

Click Submit Payment to purchase software1

1Source:Ubuntu Software Center Documentation

If the App is free, but shows the buy button and $0.00 like the app in the image below, after you login, you will get

And below is the final outcome. The App was installed without paying a dime.